turn something on its head—(also: stand something on its head) cause a complete reversal of what is regarded as the norm:
- Suddenly, Jayne’s once sane life is turned on its head, and not even her closest friends are what they seem.
turn something upside down—
1. reverse smth. physically:
- Wolfe uncorked the bottle and turned it upside down. The water splashed the stones at Turrell’s feet.
2. = turn something on its head:
- That would have turned charity tax law upside down.
3. search everywhere in a place, especially roughly:
- The police turned his flat upside down looking for drugs.